// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// TODO(kenton):  Use generics?  E.g. Builder<BuilderType extends Builder>, then
//   mergeFrom*() could return BuilderType for better type-safety.

package com.google.protobuf;

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;

/**
 * Abstract interface implemented by Protocol Message objects.
 *
 * <p>See also {@link MessageLite}, which defines most of the methods that typical users care about.
 * {@link Message} adds to it methods that are not available in the "lite" runtime. The biggest
 * added features are introspection and reflection -- i.e., getting descriptors for the message type
 * and accessing the field values dynamically.
 *
 * @author kenton@google.com Kenton Varda
 */
public interface Message extends MessageLite, MessageOrBuilder {

    // (From MessageLite, re-declared here only for return type covariance.)
    @Override
    Parser<? extends Message> getParserForType();


    // -----------------------------------------------------------------
    // Comparison and hashing

    /**
     * Compares the specified object with this message for equality. Returns {@code true} if the given
     * object is a message of the same type (as defined by {@code getDescriptorForType()}) and has
     * identical values for all of its fields. Subclasses must implement this; inheriting {@code
     * Object.equals()} is incorrect.
     *
     * @param other object to be compared for equality with this message
     * @return {@code true} if the specified object is equal to this message
     */
    @Override
    boolean equals(Object other);

    /**
     * Returns the hash code value for this message. The hash code of a message should mix the
     * message's type (object identity of the descriptor) with its contents (known and unknown field
     * values). Subclasses must implement this; inheriting {@code Object.hashCode()} is incorrect.
     *
     * @return the hash code value for this message
     * @see Map#hashCode()
     */
    @Override
    int hashCode();

    // -----------------------------------------------------------------
    // Convenience methods.

    /**
     * Converts the message to a string in protocol buffer text format. This is just a trivial wrapper
     * around {@link TextFormat.Printer#printToString(MessageOrBuilder)}.
     */
    @Override
    String toString();

    // =================================================================
    // Builders

    // (From MessageLite, re-declared here only for return type covariance.)
    @Override
    Builder newBuilderForType();

    @Override
    Builder toBuilder();

    /**
     * Abstract interface implemented by Protocol Message builders.
     */
    interface Builder extends MessageLite.Builder, MessageOrBuilder {
        // (From MessageLite.Builder, re-declared here only for return type
        // covariance.)
        @Override
        Builder clear();

        /**
         * Merge {@code other} into the message being built. {@code other} must have the exact same type
         * as {@code this} (i.e. {@code getDescriptorForType() == other.getDescriptorForType()}).
         *
         * <p>Merging occurs as follows. For each field:<br>
         * * For singular primitive fields, if the field is set in {@code other}, then {@code other}'s
         * value overwrites the value in this message.<br>
         * * For singular message fields, if the field is set in {@code other}, it is merged into the
         * corresponding sub-message of this message using the same merging rules.<br>
         * * For repeated fields, the elements in {@code other} are concatenated with the elements in
         * this message.<br>
         * * For oneof groups, if the other message has one of the fields set, the group of this message
         * is cleared and replaced by the field of the other message, so that the oneof constraint is
         * preserved.
         *
         * <p>This is equivalent to the {@code Message::MergeFrom} method in C++.
         */
        Builder mergeFrom(Message other);

        // (From MessageLite.Builder, re-declared here only for return type
        // covariance.)
        @Override
        Message build();

        @Override
        Message buildPartial();

        @Override
        Builder clone();

        @Override
        Builder mergeFrom(CodedInputStream input) throws IOException;

        @Override
        Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
                throws IOException;

        /**
         * Get the message's type's descriptor. See {@link Message#getDescriptorForType()}.
         */
        @Override
        Descriptors.Descriptor getDescriptorForType();

        /**
         * Create a builder for messages of the appropriate type for the given field. The
         * builder is NOT nested in the current builder. However, messages built with the
         * builder can then be passed to the {@link #setField(Descriptors.FieldDescriptor, Object)},
         * {@link #setRepeatedField(Descriptors.FieldDescriptor, int, Object)}, or
         * {@link #addRepeatedField(Descriptors.FieldDescriptor, Object)}
         * method of the current builder.
         *
         * <p>To obtain a builder nested in the current builder, use
         * {@link #getFieldBuilder(Descriptors.FieldDescriptor)} instead.
         */
        Builder newBuilderForField(Descriptors.FieldDescriptor field);

        /**
         * Get a nested builder instance for the given field.
         *
         * <p>Normally, we hold a reference to the immutable message object for the message type field.
         * Some implementations(the generated message builders), however, can also hold a reference to
         * the builder object (a nested builder) for the field.
         *
         * <p>If the field is already backed up by a nested builder, the nested builder will be
         * returned. Otherwise, a new field builder will be created and returned. The original message
         * field (if exist) will be merged into the field builder, which will then be nested into its
         * parent builder.
         *
         * <p>NOTE: implementations that do not support nested builders will throw <code>
         * UnsupportedOperationException</code>.
         */
        Builder getFieldBuilder(Descriptors.FieldDescriptor field);

        /**
         * Get a nested builder instance for the given repeated field instance.
         *
         * <p>Normally, we hold a reference to the immutable message object for the message type field.
         * Some implementations(the generated message builders), however, can also hold a reference to
         * the builder object (a nested builder) for the field.
         *
         * <p>If the field is already backed up by a nested builder, the nested builder will be
         * returned. Otherwise, a new field builder will be created and returned. The original message
         * field (if exist) will be merged into the field builder, which will then be nested into its
         * parent builder.
         *
         * <p>NOTE: implementations that do not support nested builders will throw <code>
         * UnsupportedOperationException</code>.
         */
        Builder getRepeatedFieldBuilder(Descriptors.FieldDescriptor field, int index);

        /**
         * Sets a field to the given value. The value must be of the correct type for this field, i.e.
         * the same type that {@link Message#getField(Descriptors.FieldDescriptor)} would return.
         */
        Builder setField(Descriptors.FieldDescriptor field, Object value);

        /**
         * Clears the field. This is exactly equivalent to calling the generated "clear" accessor method
         * corresponding to the field.
         */
        Builder clearField(Descriptors.FieldDescriptor field);

        /**
         * Clears the oneof. This is exactly equivalent to calling the generated "clear" accessor method
         * corresponding to the oneof.
         */
        Builder clearOneof(Descriptors.OneofDescriptor oneof);

        /**
         * Sets an element of a repeated field to the given value. The value must be of the correct type
         * for this field, i.e. the same type that {@link
         * Message#getRepeatedField(Descriptors.FieldDescriptor, int)} would return.
         *
         * @throws IllegalArgumentException The field is not a repeated field, or {@code
         *                                  field.getContainingType() != getDescriptorForType()}.
         */
        Builder setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value);

        /**
         * Like {@code setRepeatedField}, but appends the value as a new element.
         *
         * @throws IllegalArgumentException The field is not a repeated field, or {@code
         *                                  field.getContainingType() != getDescriptorForType()}.
         */
        Builder addRepeatedField(Descriptors.FieldDescriptor field, Object value);

        /**
         * Set the {@link UnknownFieldSet} for this message.
         */
        Builder setUnknownFields(UnknownFieldSet unknownFields);

        /**
         * Merge some unknown fields into the {@link UnknownFieldSet} for this message.
         */
        Builder mergeUnknownFields(UnknownFieldSet unknownFields);

        // ---------------------------------------------------------------
        // Convenience methods.

        // (From MessageLite.Builder, re-declared here only for return type
        // covariance.)
        @Override
        Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException;

        @Override
        Builder mergeFrom(InputStream input) throws IOException;

        @Override
        Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
                throws IOException;

        @Override
        boolean mergeDelimitedFrom(InputStream input) throws IOException;

        @Override
        boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
                throws IOException;
    }
}
